Granted I tuned mine "down" to 91 octane (actually improved power and torque). The FR-S was actually tuned for 93 octane from the factory since the majority of the US has 93 readily available. I mixed 3.5 gallons of this 100 octane with the rest of my 91 octane to get a mix slightly higher than 93 octane. She mainly sits now days with DD duties going towards my Yaris, so I figured it'll be better to have that 93 mix in the tank.

Iron-X is really pungent. I was wearing an R95 respirator, gloves, and eye protection when spraying it on. Even with the respirator, I could smell it. I heard neighbors down the street coughing too. Careful if you use it, and try to spray upwind. I got some overspray on my arms; luckily I don't smell that bad.